The president of Microsoft International, Jean-Philippe Courtois, is equally impressed: "Vista is the biggest launch ever" in Microsoft's history, more important than Windows 95.

Considering the hype, it must be worrying for Microsoft that many technology experts believe that Vista is at best accomplished but not really a breakthrough.

Vista, they say, is not any better than OS X, the operating system of rival Apple.

VISTA PC SPECIFICATIONS

VISTA CAPABLE

800MHz processor

512Mb memory

DirectX9 capable graphics processor

PREMIUM READY

1GHz processor

1Gb memory

128Mb graphics memory

40Gb hard drive

DVD-ROM

Internet access

Corporate IT bosses are not impressed either, surveys suggest. Some will move to Vista for security reasons, says George Colony, chief executive of technology consulting firm Forrester, but most will do so because Microsoft is forcing them.

While corporate users may have little choice, it's with consumers where Vista will have to prove its mettle. Here Microsoft has not just to capture the market, but also inspire it.

Only if Vista delivers its promise of managing the digital lifestyle will it become the central hub of consumers' connected world.

Success by default?

Let's make no mistake: Windows Vista will be a success. But it will happen almost by default.

Corporate IT administrators are tied into Microsoft's network architecture, while consumers will probably pick a PC because they trust brands such as HP, Dell or Sony and because PC manufacturers simply take up more shelf space than Apple's narrow product range.

"Very few consumers will choose to upgrade to Vista," says Mr Colony. "Nobody is choosing to install it, they will upgrade only by buying a new machine."

Forrester estimates that by the end of this year, Vista will have a 15% share of the North American consumer market, which amounts to about 12.2 million units. By 2011 it expects Vista to have 70% of the market, or just over 73 million installations.

Considering that Windows is one of Microsoft's two big profit engines (the other is the productivity software Office), executives at the company headquarters in Redmond, Washington, can probably relax.

But these numbers do not secure Microsoft's future in a rapidly evolving tech landscape.

The problem, says Mr Colony, is Microsoft's brand perception: A Forrester survey of 50,000 consumers suggests that Microsoft is the consumer brand with the highest number of installations, but also the company with the second-lowest approval rating among its customers, says Mr Colony.

'Vista is user-centric'

Vista is supposed to change that perception and "wow" computer users.

Microsoft hopes to capture people's minds

When you use Vista, "it's just not like using software anymore... it's more user-centric, less systems-centric," says Mr Gates, who is also the firm's chief software architect.

To make the right first impression, Microsoft has scheduled big launch events in 50 countries. In Paris, for example, fireworks will light the sky that will be larger than those at the start of the new millennium.

"This is about capturing the minds of the people," says Mr Courtois. "They have problems [with their computers], need help" and Vista is going to provide it.

The boss of Microsoft International tries to explain:

Looks: Vista looks much prettier than XP, with a 3D feel to it and see-through windows.

Security: "The company has learned its lessons, and Bill Gates was leading the work to make security central to Vista." The software will be secure by design and by default, he says, with all security options switched on straight out of the box. Better back-up software will protect your digital memories, parental controls will safeguard your children, and strong encryption software will ensure that a stolen laptop or PC will not give up your personal secrets (although this part of Vista is available only in Vista's most expensive version).

Connectivity: Whatever kind of device you want to connect to, eg using Wifi or Bluetooth, Vista will make it easier; and a new "meeting room" allows users to share a virtual workspace between computers in the same area.

Fun and entertainment: The gaming technology in Vista has "increased significantly". Better graphics boost the quality of game play, and the popular Flight Simulator, for example, now integrates real-time weather conditions. Watching and working with photos, music and videos has been improved, Mr Courtois says, and Vista comes integrated with Microsoft's Media Centre, which is optimised to watch media on a television.

Search: A fully integrated search function makes it easy to find the needles in the rapidly growing haystacks of our digital lives.

Microsoft has not left much to chance. To iron out bugs, some five million people have tested Vista over the past year or two.

In your living room

Microsoft's biggest challenge, however, will be for Windows to make the jump from the study into our living rooms.

VISTA HOME VERSIONS

Home Basic - improved search and security but no Aero interface (pictured)

Irritatingly for Microsoft executives, this make-or-break move is out of the company's control.

Windows is a platform; Microsoft's partners build on it by providing hardware and software.

If the industry develops and sells products with the right form factor, combining the beauty and simplicity of hi-fi equipment with the Vista operating system, Microsoft will sit at the top of our digital world.

Forrester's George Colony is dubious about Microsoft's chances of success: "Operating systems crash, they don't give you any pleasure," he says. "It's still too difficult to install and administer computers."

'Two sets of idiots'

So what about the long-awaited convergence between PCs and consumer electronics?

Niklas Zennstroem, the co-founder of internet telephony success Skype and backer of video-on-demand service Joost.com, believes that the "computerisation of television sets" is just a few years away.

Mr Colony is more sceptical: "You have two sets of idiots here, the PC idiots and the TV idiots," he says, and neither understands yet how to make convergence work.

So if Microsoft's hardware partners fail to deliver, the company has a problem.

Mr Courtois for his part points to "an incredible variety of form factors" in the pipeline, from media centres to what he calls "ultra-mobile PCs".

Why the rivals don't deliver

Microsoft's weakness, however, is also its biggest strength.

Rival Apple may grab the headlines (and the biggest share of the MP3 player market), but in the computer space it is puny.

The reason: Apple insists on controlling the whole package, from the operating system to the central hardware.

As a result, Apple lacks the breadth of hard- and software that attracts customers.

Apple may glow in the halo of its iconic iPods and gain kudos from the tech-savvy crowd. But so far, the shallowness of Apple's industrial ecosystem has made the firm's offering pricey and limited its success in the market place.

Microsoft's other rival, the open-source Linux operating system, has a similar problem.

Even though products like Ubuntu and Suse Linux show great promise, there are still issues with compatibility and ease of use.

Beyond Vista

But as Microsoft celebrates Vista, the company is already thinking about what comes next.

Consumers had to wait five years for the new operating system. A gap that long won't be allowed again, promises Mr Courtois.

But as it works on the next incarnation of Windows, Microsoft will have to face a profound shift in the world of software.

More and more companies are offering software online as a service. All that users need is a good browser.

And that could make operating systems somewhat irrelevant.

Last chance

So why is Vista so important?

HAVE YOUR SAY

I'll run Linux on most of my machines, it does everything I need much more easily than windows